The present invention relates generally to equipment utilized in conjunction with pipeline operations and, in an embodiment described herein, more particularly provides a pipeline padding machine with a debris-resistant escalator assembly.
In constructing pipelines, a ditch is typically dug by excavating material from the ground, and then a pipe (including many interconnected pipe sections) is positioned in the ditch. The excavated material can include objects (such as large rocks, sharp objects, etc.) which could damage the pipe or otherwise hinder the pipeline operation (such as by creating large voids in the ditch, etc.).
Therefore, instead of merely covering the pipe by pushing the excavated material back into the ditch, only a portion of the excavated material is used around the pipe in the ditch. This portion of the excavated material is the relatively fine portion and is known to those skilled in the art as “padding” since it forms a protective layer surrounding the pipe. The remainder of the excavated material can be deposited in the ditch above the padding if desired.
Several machines have been developed to separate the padding from the remainder of the excavated material and place the padding in the ditch about the pipe. However, these prior padding machines typically have one or more shortcomings. For example, these padding machines may include escalator flights which permit an inordinate amount of the excavated material to pass through the flights and hinder operation of the track, drive mechanism, etc. below.
Therefore, it may be seen that improvements are needed in the art of pipeline padding machines. It is among the objects of the present invention to provide such improvements.